Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
feets wrote ... The 1973 Kelsey Hayes brake calipers had a 2.75" piston. That gives it 5.939" of surface area on the piston. The Budd caliper has 4 pistons at 2.36" in diameter. That gives it 8.748" of surface area (you only calculate one side of a multi-piston caliper).
I'm not sure how big the master cylinder is on the Budd system but there's a good chance it will be too big for a Kelsey Hays setup. Pedal effort will be much higher even with power assist. You may want to look into the matching master cylinder and replace the factory proportioning valve with the adjustable unit.
The master cylinder on my 1967 Budd brakes is 1 1/8" bore while the 1973 master cylinder is 1 1/32" bore. I was going to replace the master cylinder that I have with a new one from 1973. The two master cylinders look the same. I am surprised at the difference. Thanks for the information.
Joined: Sun Jul 18 2010, 11:11PM
Location: DFW
Posts: 811
Good idea. That 1-1/8" MC is HUGE. When I called Wilwood to ask about the proper size MC for my 8 piston AMG brakes they suggested that size. My front calipers have four 42mm pistons and four 40 mm pistons per caliper. The rears have two 40 mm pistons and two 36 mm pistons per caliper.
My manual brake pedal ratio is different than a power brake ratio. That changes the pedal effort too.
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
feets wrote ... Good idea. That 1-1/8" MC is HUGE. When I called Wilwood to ask about the proper size MC for my 8 piston AMG brakes they suggested that size. My front calipers have four 42mm pistons and four 40 mm pistons per caliper. The rears have two 40 mm pistons and two 36 mm pistons per caliper.
My manual brake pedal ratio is different than a power brake ratio. That changes the pedal effort too.
I just received the Wilwood adjustable proportioning valve yesterday. It looks nice BUT the rear out line and the two front out lines all originate on the same side of the valve. I will have to make a 180 degree turn on one of the line or 90 degree turns on all of them. This does not seem like a very smart design!
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
Excuse me if this a dumb question, but how is this fancy 2 in and 3 out valve install?
Am I correct to assume the master cylinder front section goes to one inlet and the Master cylinder rear section goes to the other input. Of the three outlets, one goes to right front, one goes to left front and the third goes to a "T" which feeds the right and left rear brakes.
When you turn the adjustment knob, does it open or close the feed going to the rear "T". The single in and dual out to the fronts is basically a non-adjustable "T" The switch detects a pressure differential between the front and rear circuits and drives the idiot light on the dash.
If all this true, why not just leave the stock distribution block and idiot light switch in place and use a simple 1 in and 1 out adjustable valve in the line running to the rear "T".
My car has factory front disc (Kelsey Hayes single piston floating caliper) and its plumbing is a little different. There is a 2 in 3 out distribution block with idiot light like the on you have, except its not adjustable. One of the front outlets is plugged and the other feeds what Mopar calls a Metering Valve Assembly which looks like a "T" block to distribute to the two front brakes. There is a valve in the this block that completely shuts off between 3 and 135 psi making bleeding interesting. I'm not really sure why this was used or if it was a one year only idea that didn't work.
In the Service manual they show Satellite models as using a rear proportioning valve and its a simple 1 in, 1 out adjustable valve mounted in the rear line and bolted to the frame rail.
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
Fury440 wrote ... Excuse me if this a dumb question, but how is this fancy 2 in and 3 out valve install?
Am I correct to assume the master cylinder front section goes to one inlet and the Master cylinder rear section goes to the other input. Of the three outlets, one goes to right front, one goes to left front and the third goes to a "T" which feeds the right and left rear brakes.
When you turn the adjustment knob, does it open or close the feed going to the rear "T". The single in and dual out to the fronts is basically a non-adjustable "T" The switch detects a pressure differential between the front and rear circuits and drives the idiot light on the dash.
If all this true, why not just leave the stock distribution block and idiot light switch in place and use a simple 1 in and 1 out adjustable valve in the line running to the rear "T".
My car has factory front disc (Kelsey Hayes single piston floating caliper) and its plumbing is a little different. There is a 2 in 3 out distribution block with idiot light like the on you have, except its not adjustable. One of the front outlets is plugged and the other feeds what Mopar calls a Metering Valve Assembly which looks like a "T" block to distribute to the two front brakes. There is a valve in the this block that completely shuts off between 3 and 135 psi making bleeding interesting. I'm not really sure why this was used or if it was a one year only idea that didn't work.
In the Service manual they show Satellite models as using a rear proportioning valve and its a simple 1 in, 1 out adjustable valve mounted in the rear line and bolted to the frame rail.
A couple pictures
Good questions: This all goes to why I started this thread in the first place. The question then is does my 1967 Polara with the Budd disc brakes actually have a real proportioning valve or is it just a distribution block. If it is a proportioning valve then you should not install a second proportioning valve in thre same line. If it is a distribution block then your suggestion of the simple 1 in 1 out valve in the rear line should work. Note that there is an electronic pressure switch on the proportioning valve that I purchased from Wilwood. However it simply monitors the presence of pressure in the valve to be used to activate the brake lights if you want. The switch in the factory "proportioning" valves measures a difference in pressure between the front and rear lines to show that you have a loss of pressure in one of the lines. On the valve that I have just purchased the front line is not adjustable and the valve only controls the pressure to the rear line. I believe that my 1969 Imperial with Budd discs is plumbed the same as your car with the separate valve in the front line.